As a result of a shortage of fuel, inflation of gasoline prices and high labor costs, self-service gasoline stations from which gasoline is purchased at a reduced rate have become popular. However, for various reasons, some customers have not utilized self-service gasoline pumps to a maximum extent.
The cap on a gasoline tank is often covered with dirt and grease which results in a strong likelihood that the customer will soil his hands and possibly his clothes when the cap is removed to fill the fuel tank and replaced.
In view of emission control standards established to protect the environment, vehicle designers have developed systems to prevent leakage of fuel and vapor from the fuel tank. Improper connection of the gas cap to a vehicle fuel tank presents a potential fire hazard and also permits leakage of vapor from the tank of the vehicle.
In addition to numerous problems encountered by unskilled persons removing and replacing the gas cap, service station attendants occasionally forget to replace the cap or improperly replace it resulting in loss of the gas cap.
U.S. Pat. Nos. 1,810,019; 1,818,608; 1,982,879; 2,503,031; 2,593,712; 2,657,824; 2,765,948; and 3,897,810 disclose self closing caps for fuel tanks, radiators and the like.
U.S. Pat. No. 3,911,977 and Canadian Pat. No. 999,247 disclose filler necks having an unleaded door contained therein.
U.S. Pat. No. 3,937,358 discloses a venting system. Systems of this type are unduly complicated increasing the cost of the cap and problems which may occur causing premature failure.
Self closing caps heretofore devised are not suitable for replacement of the conventional gas cap, radiator caps and the like on modern vehicles without substantially modifying the neck of the tank. Self-closing caps heretofore devised have not offered sealing capability required to meet existing emission control regulations and to permit use of the cap or filling the tank without removing the cap or alternately to permit removal of the cap if deemed expedient to do so without the use of tools.